Declaring Methods

Part of the Fundamentals section of Coddy's C# journey — lesson 49 of 69.

A method is a sequence of code that has a name. The purpose of a method is to reuse a piece of code multiple times.

For example, take a look at this code:

Console.WriteLine("Welcome to Coddy");
Console.WriteLine("New session...");
Console.WriteLine("Welcome to Coddy");
Console.WriteLine("Another session...");
Console.WriteLine("Welcome to Coddy");

We use the same code Console.WriteLine("Welcome to Coddy") over and over again. Another issue with this code is that if we wanted to change the message: Welcome to Coddy to something different, like Welcome aboard it would have to change 3 different lines of code. To solve this issue, we will use methods.

To declare a method, we use the following syntax:

access_modifier [modifiers] return_type method_name(parameters) {
	// code
}

For our example, we will create a method named Greet and it will look like this:

public static void Greet() {
	Console.WriteLine("Welcome to Coddy");
}

If we break it down:

public is the access modifier (controls who can use this method)
static is a modifier (means the method belongs to the class itself)
void is the return type (means it doesn't return any value)
Greet is the method name
() contains parameters (empty here)

For now, just always write public static before your method name - we'll explain what each word means later.

To use/call/execute the method, we write Greet();:

Greet();
Console.WriteLine("New session...");
Greet();
Console.WriteLine("Another session...");
Greet();

This will result in the same output as above.

Note: In C#, the order of method declarations within a class does not matter. The compiler reads the entire class first, so a method can be called before or after its definition in the source code — both are valid.

For example, both of these are correct in C#:

// Method defined FIRST, then called
public static void Greet() {
    Console.WriteLine("Welcome to Coddy");
}

Greet();
Console.WriteLine("New session...");
Greet();

// Method called FIRST, defined after — also valid in C#
Greet();
Console.WriteLine("New session...");
Greet();

public static void Greet() {
    Console.WriteLine("Welcome to Coddy");
}

Challenge

Easy

Write a program that gets one input, a number. The input number indicates how many times to execute the below method.

Create a method that calculates the sum of all of the numbers between 1 and 1000 (including) and prints it, name the method however you like.

Cheat sheet

A method is a sequence of code that has a name, used to reuse code multiple times.

Method syntax:

access_modifier return_type method_name(parameters) {
	// code
}

Example method declaration:

public static void Greet() {
	Console.WriteLine("Welcome to Coddy");
}

To call/execute a method:

Greet();

Note: In C#, the order of method declarations does not matter — a method can be called before or after its definition, as long as it is defined within the same class.

Try it yourself

using System;

public class Program {
    // Method declaration
    public static void SumNumbers() {
        // Complete Method
        
    }
    
    
    public static void Main(string[] args) {
        int n = int.Parse(Console.ReadLine());
        for (int i = 0; i < n; i++) {
            // Call the method n times
        }
    }
}